Highest ratio of separation area to volume of membranes can be achieved by the use of hollow fiber configuration. Ceramic hollow fibers with outer diameters no larger than 1 mm are used as supports for dense Pd membranes. Pd layers of 2-3 mum thick are deposited by electroless plating technique. H-2 permeances are 7-10 m(3)/m(2) h bar at 350-450 degreesC. The durability in H-2 is tested at 430 degreesC for 800 h. H-2 permeance keeps over 10 m(3)/m(2) h bar and the separation factor of H-2/N-2 over 1000, which shows the possibilities to be applied in H-2 separation and catalysis at high temperatures. (C) 2003 Elsevier Science B.V. All rights reserved.